On September 29, 1833, King Ferdinand VII of Spain died. When Carlos Maria Isidro, who was then in Portugal, heard the news, he declared himself King of Spain on October 1, 1833, and took the name Charles V.
But on the very day Ferdinand VII died, Queen Maria Cristina had already proclaimed Isabella II queen, making her the Queen of Spain, while Maria Cristina herself became Isabella II's regent.
On October 4, 1833, the Carlists launched an uprising. On October 17, Regent Christina stripped Carlos of his title of prince and all his powers, and confiscated his property.
The First Carlist War broke out.
In fact, Ferdinand VII had issued a law similar to the Pragmatic Sanction as early as 1830, abolishing the Salic Law and allowing women to inherit the Spanish throne.
The Pragmatic Sanction met with widespread opposition. Most of the great nobles and Catholic clergy sided with Carlos.
But Carlos himself had little political wisdom and no political finesse.
In essence, the regent and Carlos were cut from the same cloth. They both hated liberalism and considered everyone outside the nobility less than human. She loved court intrigue and infighting, and adored the absolute authority enjoyed by monarchs under an autocratic system.
Yet the first thing she did after taking power was win the Liberals' support and put on a show of being close to the people.
Though she loathed the Liberals and commoners, she still appointed a Liberal leader of common birth as Spain's prime minister.
The regent then made the great nobles and Catholic clergy unrealistic promises, claiming she would not only protect their rightful interests but even establish annuities to reward those loyal to Spain's legitimate ruler.
After Regent Christina made her moves, the balance of power between the two sides was completely reversed.